1. Field of the Invention
The present invention relates to an imaging cartridge having the function of forming images in a copying machine, fax machine, printer, image displaying apparatus or the like.
2. Description of Related Art
In the field of corona charging device which is incorporated in an imaging cartridge or the like, it has been devised that an electrode strip or a coronode with pin-like electrodes is held between insulating blocks and mounted to a shielding member, with a grid member mounted thereabove, as disclosed in Japanese Published Unexamined Patent Applications 4-133075 and 4-217276.
Other prior art arrangements include a corona charging device comprising a coronode with pin-like electrodes disposed in such a way that the pin-like electrodes are faced to an intermediate member arranged between the electrodes and a surface to be charged, as described in Japanese Published Unexamined Patent Application 5-165302. Also, Japanese Published Unexamined Patent Application 5-46000 discloses an arrangement in which an electrode unit comprising a pin corotron held between elongated support members is laterally slid into a matching concave of a main body of an apparatus for installation.
The entire body of an imaging cartridge had been conventionally constructed to be disposable, but it has recently been desired to produce reusable cartridges because of environmental problems. This trend has created significant requirements such as simplifying an exchanging operation of discharging members which tend to wear out most in a corona charging device, as well as simplifying the maintenance and repairing operation by a serviceman or a user.
However, an imaging cartridge is usually comprised of a corona charging device and an object to be charged, both of which function to form images, necessitating a complicated and troublesome exchanging operation, including the steps of dismounting the corona charging device and the object to be charged out of the imaging cartridge body, removing a grid member from the corona charging device, and taking out the discharging electrode members.
Further, in the above-described prior art arrangements, in order to remove the grid member, the corona charging device after being taken out from the imaging cartridge is first laid in such a way that the grid member faces upward, and the grid member is upwardly removed therefrom. The grid member may be deformed to contact thereto, causing damage to the discharging electrodes by external force during such operation or by inadvertently dropping the grid member. When the discharging electrodes are pin-like members, the electrodes may be bent or crushed by some chance, which causes irregular discharges and increases generation of ozone. When the discharging electrodes are wire members, the wire may be cut or a plated surface layer such as gold or the like may be peeled off by the above-mentioned inadvertent operations. There remain the same problems when installing the discharging electrodes, since the installing operation is similarly complicated such as having to mount the grid member after installing the discharging electrodes.
Thus, even a highly skilled serviceman needs quite a long time for repairing or maintenance, and it is very difficult for an ordinary user to exchange the discharging electrodes on his own. This operation could be easily done by the user if the entire corona charging device is to be exchanged, which means, however, that other elements that are still usable are wasted, and thus this approach is unacceptable from economical and ecological view points.
When the corona charging device has no grid members, the discharging electrodes can be more easily exchanged, but it is still rather troublesome to have to first dismount the corona charging device from the imaging cartridge before exchanging the electrodes.